code: def test_ttest(self):
      tt = self.res.t_test(np.eye(len(self.res.params)))
      from scipy import stats
  
      pvalue = stats.norm.sf(np.abs(tt.tvalue)) * 2
      assert_almost_equal(tt.tvalue, self.res.tvalues, DEC)
      assert_almost_equal(pvalue, self.res.pvalues, DEC)
  
imports: import pytest
  import numpy
  from numpy.testing import assert_almost_equal
  from scipy import stats
  import statsmodels.api
  from statsmodels.miscmodels.count import PoissonGMLE, PoissonOffsetGMLE, PoissonZiGMLE
  from statsmodels.discrete.discrete_model import Poisson
  from statsmodels.tools.sm_exceptions import ValueWarning
label_desc: Use image node_id 3 for calling the CompareMixin obj's underlying member method code with example usage: obj.test_ttest() without return types